package practice.w917;

public class StringBuilderDemo {
    public static void main(String[] args) {
        String str = "好好学习Java";
        StringBuilder builder = new StringBuilder(str);
        builder.append(",为了找个好工作");
        System.out.println(builder);
        builder.replace(9,16,"就是为了改变世界");
        System.out.println(builder);
        builder.delete(0,8);
        System.out.println(builder);
        builder.insert(0,"活着");
        System.out.println(builder);
        builder.reverse();
        System.out.println(builder);
        StringBuilder builder1 = new StringBuilder("a");
        for(int i=0;i<1000000;i++){ //100万次
            builder1.append("a");
        }
        System.out.println("执行完毕");

//        String str = "好好学习Java";
//        StringBuilder builder = new StringBuilder(str);
//        builder.append(",为了找个好工作");
//        System.out.println(builder);
//        builder.replace(9,16,"就是为了改变世界");
//        System.out.println(builder);
//        builder.delete(0,8);
//        System.out.println(builder);
//        builder.insert(0,"活着");
//        System.out.println(builder);
//        builder.reverse();
//        System.out.println(builder);
//        StringBuilder builder1 = new StringBuilder("a");
//        for(int i=0;i<1000000;i++){ //100万次
//            builder1.append("a");
//        }
//        System.out.println("执行完毕");



    }
}










